U.S. patent number 10,208,678 [Application Number 15/125,331] was granted by the patent office on 2019-02-19 for gas turbine combustion control device and combustion control method and program therefor.
This patent grant is currently assigned to MITSUBISHI HITACHI POWER SYSTEMS, LTD.. The grantee listed for this patent is MITSUBISHI HITACHI POWER SYSTEMS, LTD.. Invention is credited to Wataru Akizuki, Hideki Haruta, Yoshifumi Iwasaki, Yuji Komagome, Koji Takaoka, Noriyoshi Uyama.
![](/patent/grant/10208678/US10208678-20190219-D00000.png)
![](/patent/grant/10208678/US10208678-20190219-D00001.png)
![](/patent/grant/10208678/US10208678-20190219-D00002.png)
![](/patent/grant/10208678/US10208678-20190219-D00003.png)
![](/patent/grant/10208678/US10208678-20190219-D00004.png)
![](/patent/grant/10208678/US10208678-20190219-D00005.png)
![](/patent/grant/10208678/US10208678-20190219-D00006.png)
![](/patent/grant/10208678/US10208678-20190219-D00007.png)
![](/patent/grant/10208678/US10208678-20190219-D00008.png)
![](/patent/grant/10208678/US10208678-20190219-D00009.png)
![](/patent/grant/10208678/US10208678-20190219-D00010.png)
View All Diagrams
United States Patent |
10,208,678 |
Uyama , et al. |
February 19, 2019 |
Gas turbine combustion control device and combustion control method
and program therefor
Abstract
A combustion control device (50) is installed in a gas turbine
including a compressor (2), combustors (3), a turbine (4), a bleed
air pipe (12) through which bleed air is returned to an inlet of an
air intake facility (7), and an air bleed valve (22) that regulates
the amount of bleed air extracted. The combustion control device
(50) includes: a fuel distribution setting unit (70) that sets a
turbine inlet temperature or a turbine inlet temperature-equivalent
control variable on the basis of input data, and sets fuel
distribution ratios on the basis of the turbine inlet temperature
or the turbine inlet temperature-equivalent control variable; and a
fuel valve opening setting section (81) that sets the valve
openings of fuel regulating valves. The fuel distribution setting
unit (70) includes correction means for modifying the fuel
distribution ratios.
Inventors: |
Uyama; Noriyoshi (Yokohama,
JP), Haruta; Hideki (Yokohama, JP),
Akizuki; Wataru (Yokohama, JP), Komagome; Yuji
(Yokohama, JP), Takaoka; Koji (Yokohama,
JP), Iwasaki; Yoshifumi (Yokohama, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI HITACHI POWER SYSTEMS, LTD. |
Kanagawa |
N/A |
JP |
|
|
Assignee: |
MITSUBISHI HITACHI POWER SYSTEMS,
LTD. (Kanagawa, JP)
|
Family
ID: |
54195506 |
Appl.
No.: |
15/125,331 |
Filed: |
March 24, 2015 |
PCT
Filed: |
March 24, 2015 |
PCT No.: |
PCT/JP2015/058950 |
371(c)(1),(2),(4) Date: |
September 12, 2016 |
PCT
Pub. No.: |
WO2015/146994 |
PCT
Pub. Date: |
October 01, 2015 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20170074175 A1 |
Mar 16, 2017 |
|
Foreign Application Priority Data
|
|
|
|
|
Mar 25, 2014 [JP] |
|
|
2014-061915 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02C
3/04 (20130101); F02C 9/20 (20130101); F02C
9/28 (20130101); F02C 9/18 (20130101); F02C
9/52 (20130101); F04D 29/541 (20130101); F02C
7/04 (20130101); F02C 9/16 (20130101); F05D
2270/303 (20130101) |
Current International
Class: |
F02C
9/26 (20060101); F02C 3/04 (20060101); F04D
29/54 (20060101); F02C 9/18 (20060101); F02C
9/52 (20060101); F02C 7/04 (20060101); F02C
9/28 (20060101); F02C 9/20 (20060101); F02C
9/16 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
8-178290 |
|
Jul 1996 |
|
JP |
|
9-291833 |
|
Nov 1997 |
|
JP |
|
2004-116384 |
|
Apr 2004 |
|
JP |
|
2007-77867 |
|
Mar 2007 |
|
JP |
|
4119909 |
|
Jul 2008 |
|
JP |
|
2011-137390 |
|
Jul 2011 |
|
JP |
|
2012-26449 |
|
Feb 2012 |
|
JP |
|
2013-53552 |
|
Mar 2013 |
|
JP |
|
2013-209917 |
|
Oct 2013 |
|
JP |
|
Other References
International Search Report dated Jun. 23, 2015 in International
Application No. PCT/JP2015/058950 (with English translation). cited
by applicant .
Written Opinion of the International Searching Authority dated Jun.
23, 2015 in International Application No. PCT/JP2015/058950 (with
English translation). cited by applicant.
|
Primary Examiner: Rodriguez; William H
Attorney, Agent or Firm: Wenderoth, Lind & Ponack,
L.L.P.
Claims
The invention claimed is:
1. A gas turbine combustion control device that is installed in a
gas turbine including: a compressor having inlet guide vanes; a
combustor having a plurality of fuel nozzles; a turbine; a bleed
air pipe through which bleed air from a casing is returned to an
inlet of an air intake facility; and an air bleed valve that is
mounted on the bleed air pipe and regulates the amount of bleed air
extracted, the gas turbine combustion control device being
configured to set fuel distribution ratios for fuel circuits of
fuel supplied to the combustor and being operable to perform: a
fuel distribution setting that sets a turbine inlet temperature or
a turbine inlet temperature-equivalent control variable computed on
the basis of input data, and sets the fuel distribution ratios on
the basis of the turbine inlet temperature or the turbine inlet
temperature-equivalent control variable; and a valve opening
setting that sets the valve openings of fuel regulating valves
provided in the fuel circuits on the basis of the fuel distribution
ratios, wherein in the fuel distribution setting the fuel
distribution ratios are modified on the basis of the amount of
bleed air extracted.
2. The gas turbine combustion control device according to claim 1,
wherein the gas turbine combustion control device is further
operable to perform: a turbine inlet temperature-equivalent control
variable setting that calculates first interpolated data equivalent
to the turbine inlet temperature or the turbine inlet
temperature-equivalent control variable in a first operation mode
that is an operation mode in which the gas turbine does not perform
anti-icing operation, and second interpolated data equivalent to
the turbine inlet temperature or the turbine inlet
temperature-equivalent control variable in a second operation mode
that is an anti-icing operation mode in which a constant amount of
bleed air is set and part of the bleed air from the casing is
circulated to the air intake facility; and a fuel distribution
correction that, using the first interpolated data and the second
interpolated data, modifies the fuel distribution ratios in a
predetermined operation mode on the basis of a specific parameter
determined by the amount of bleed air extracted in the
predetermined operation mode that is an anti-icing operation mode
in which an amount of bleed air required for anti-icing operation
is selected and that amount of bleed air is circulated to the air
intake facility.
3. The gas turbine combustion control device according to claim 1,
wherein the gas turbine combustion control device is further
operable to perform: an interpolated output data calculation that
calculates first interpolated output data related to an output
during no load operation in a first operation mode that is an
operation mode in which the gas turbine does not perform anti-icing
operation, and second interpolated output data related to an output
during rated load operation in the first operation mode; an
interpolated output data correction that modifies the first
interpolated output data and the second interpolated output data on
the basis of a specific parameter determined by the amount of bleed
air extracted in a predetermined operation mode that is an
anti-icing operation mode in which an amount of bleed air required
for anti-icing operation is selected and that amount of bleed air
is circulated to the air intake facility; a control variable
calculation that calculates a turbine inlet temperature-equivalent
control variable on the basis of the first modified interpolated
output data and the second modified interpolated output data that
have been modified; and a fuel distribution calculation that
calculates the fuel distribution ratios for the respective fuel
circuits on the basis of the turbine inlet temperature-equivalent
control variable.
4. The gas turbine combustion control device according to claim 3,
wherein the gas turbine combustion control device is further
operable to perform: a correction factor calculation that
calculates an output correction factor that varies according to the
specific parameter; and an interpolated output data modification
that modifies the first interpolated output data and the second
interpolated output data using the output correction factor.
5. The gas turbine combustion control device according to claim 2,
wherein the gas turbine combustion control device is further
operable to perform: a control variable interpolation that, using
the first interpolated data and the second interpolated data,
calculates a modified turbine inlet temperature or a modified
turbine inlet temperature-equivalent control variable in the
predetermined operation mode on the basis of the specific
parameter; and a fuel distribution calculation that calculates the
fuel distribution ratios for the respective fuel circuits on the
basis of the modified turbine inlet temperature or the modified
turbine inlet temperature-equivalent control variable.
6. The gas turbine combustion control device according to claim 2,
wherein the gas turbine combustion control device is further
operable to: calculate first interpolated output data related to an
output during no load operation in the first operation mode and
second interpolated output data related to an output during rated
load operation in the first operation mode; calculate first
interpolated data equivalent to the turbine inlet
temperature-equivalent control variable in the first operation mode
using the first interpolated output data and the second
interpolated output data; calculate third interpolated output data
related to an output during no load operation in the second
operation mode and fourth interpolated output data related to an
output during rated load operation in the second operation mode;
and calculate second interpolated data equivalent to the turbine
inlet temperature-equivalent control variable in the second
operation mode using the third interpolated output data and the
fourth interpolated output data.
7. The gas turbine combustion control device according to claim 2,
wherein the specific parameter is one of an intake air temperature
difference, a casing pressure ratio, the amount of bleed air, and
the valve opening of the air bleed valve.
8. A gas turbine combustion control method for a gas turbine
including: a compressor having inlet guide vanes; a combustor
having a plurality of fuel nozzles; a turbine; a bleed air pipe
through which bleed air from a casing is returned to an inlet of an
air intake facility; an air bleed valve that is mounted on the
bleed air pipe and regulates the amount of bleed air extracted; and
a gas turbine combustion control device configured to set fuel
distribution ratios for circuits of fuel supplied to the combustor,
the gas turbine combustion control method comprising the steps of:
calculating first interpolated data equivalent to a turbine inlet
temperature or a turbine inlet temperature-equivalent control
variable in a first operation mode computed on the basis of input
data on the first operation mode that is an operation mode in which
the gas turbine does not perform anti-icing operation; calculating
second interpolated data equivalent to a turbine inlet temperature
or a turbine inlet temperature-equivalent control variable in a
second operation mode computed on the basis of input data on the
second operation mode that is an anti-icing operation mode in which
a constant amount of bleed air is set and part of the bleed air
from the casing is circulated to the air intake facility; using the
first interpolated data and the second interpolated data,
calculating a modified turbine inlet temperature or a modified
turbine inlet temperature-equivalent control variable in a
predetermined operation mode on the basis of a specific parameter
determined by the amount of bleed air extracted in the
predetermined operation mode that is an anti-icing operation mode
in which an amount of bleed air required for anti-icing operation
is selected and that amount of bleed air is circulated to the air
intake facility; calculating the fuel distribution ratios for the
respective fuel circuits in the predetermined operation mode on the
basis of the modified turbine inlet temperature or the modified
turbine inlet temperature-equivalent control variable; and setting
valve openings for the respective fuel circuits on the basis of the
fuel distribution ratios.
9. A gas turbine combustion control method for a gas turbine
including: a compressor having inlet guide vanes; a combustor
having a plurality of fuel nozzles; a turbine; a bleed air pipe
through which bleed air from a casing is returned to an inlet of an
air intake facility; an air bleed valve that is mounted on the
bleed air pipe and regulates the amount of bleed air extracted; and
a gas turbine combustion control device configured to set fuel
distribution ratios for circuits of fuel supplied to the combustor,
the gas turbine combustion control method comprising the steps of:
calculating first interpolated output data corresponding to a
turbine inlet temperature related to an output during no load
operation on the basis of input data on a first operation mode that
is an operation mode in which the gas turbine does not perform
anti-icing operation; calculating second interpolated output data
corresponding to a turbine inlet temperature related to an output
during rated load operation on the basis of input data on the first
operation mode; calculating an output correction factor on the
basis of a specific parameter determined by the amount of bleed air
extracted in a predetermined operation mode that is an anti-icing
operation mode in which an amount of bleed air required for
anti-icing operation is selected and that amount of bleed air is
circulated to the air intake facility; calculating first modified
interpolated output data by modifying the first interpolated output
data on the basis of the output correction factor; calculating
second modified interpolated output data by modifying the second
interpolated output data on the basis of the output correction
factor; using the first modified interpolated output data and the
second modified interpolated output data, calculating a turbine
inlet temperature-equivalent control variable on the basis of a
turbine output in the predetermined operation mode; calculating the
fuel distribution ratios for the respective fuel circuits in the
predetermined operation mode on the basis of the turbine inlet
temperature-equivalent control variable; and setting valve openings
for the respective fuel circuits on the basis of the fuel
distribution ratios.
10. A gas turbine combustion control method for a gas turbine
including: a compressor having inlet guide vanes; a combustor
having a plurality of fuel nozzles; a turbine; a bleed air pipe
through which bleed air from a casing is returned to an inlet of an
air intake facility; an air bleed valve that is mounted on the
bleed air pipe and regulates the amount of bleed air extracted; and
a gas turbine combustion control device configured to set fuel
distribution ratios for circuits of fuel supplied to the combustor,
the gas turbine combustion control method comprising the steps of:
creating a database on the basis of input data on a first operation
mode that is an operation mode in which the gas turbine does not
perform anti-icing operation, and a database on the basis of input
data on a second operation mode that is an anti-icing operation
mode in which a constant amount of bleed air is set and part of the
bleed air from the casing is circulated to the air intake facility;
calculating first interpolated data equivalent to a turbine inlet
temperature or a turbine inlet temperature-equivalent control
variable in the first operation mode on the basis of the database;
calculating second interpolated data equivalent to a turbine inlet
temperature or a turbine inlet temperature-equivalent control
variable in the second operation mode on the basis of the database;
using the first interpolated data and the second interpolated data,
calculating a modified turbine inlet temperature or a modified
turbine inlet temperature-equivalent control variable in a
predetermined operation mode on the basis of a specific parameter
determined by the amount of bleed air extracted in the
predetermined operation mode that is an anti-icing operation mode
in which an amount of bleed air required for anti-icing operation
is selected and that amount of bleed air is circulated to the air
intake facility; calculating the fuel distribution ratios for the
respective fuel circuits in the predetermined operation mode on the
basis of the modified turbine inlet temperature or the modified
turbine inlet temperature-equivalent control variable; and setting
valve openings for the respective fuel circuits on the basis of the
fuel distribution ratios.
11. The gas turbine combustion control method according to claim 8,
wherein the specific parameter is one of an intake air temperature
difference, a casing pressure ratio, the amount of bleed air, and
the valve opening of the air bleed valve.
12. A program that executes the gas turbine combustion control
method according to claim 8.
13. The gas turbine combustion control device according to claim 5,
wherein the gas turbine combustion control device is further
operable to: calculate first interpolated output data related to an
output during no load operation in the first operation mode and
second interpolated output data related to an output during rated
load operation in the first operation mode; calculate first
interpolated data equivalent to the turbine inlet
temperature-equivalent control variable in the first operation mode
using the first interpolated output data and the second
interpolated output data; calculate third interpolated output data
related to an output during no load operation in the second
operation mode and fourth interpolated output data related to an
output during rated load operation in the second operation mode;
and calculate second interpolated data equivalent to the turbine
inlet temperature-equivalent control variable in the second
operation mode using the third interpolated output data and the
fourth interpolated output data.
14. The gas turbine combustion control device according to claim 3,
wherein the specific parameter is one of an intake air temperature
difference, a casing pressure ratio, the amount of bleed air, and
the valve opening of the air bleed valve.
15. The gas turbine combustion control device according to claim 4,
wherein the specific parameter is one of an intake air temperature
difference, a casing pressure ratio, the amount of bleed air, and
the valve opening of the air bleed valve.
16. The gas turbine combustion control device according to claim 5,
wherein the specific parameter is one of an intake air temperature
difference, a casing pressure ratio, the amount of bleed air, and
the valve opening of the air bleed valve.
17. The gas turbine combustion control method according to claim 9,
wherein the specific parameter is one of an intake air temperature
difference, a casing pressure ratio, the amount of bleed air, and
the valve opening of the air bleed valve.
18. The gas turbine combustion control method according to claim
10, wherein the specific parameter is one of an intake air
temperature difference, a casing pressure ratio, the amount of
bleed air, and the valve opening of the air bleed valve.
19. A non-transitory computer readable medium of a computer storing
a program that, when executed by the computer, performs the gas
turbine combustion control method according to claim 8.
Description
TECHNICAL FIELD
The present invention relates to gas turbine combustion control
device and combustion control method and a program therefor, and
more particularly, to a combustion control device, a combustion
control method, and a program that are applied to a gas turbine in
anti-icing operation.
The present application claims priority on Japanese Patent
Application No. 2014-061915 filed on Mar. 25, 2014, the contents of
which are incorporated herein by reference.
BACKGROUND ART
Commonly, the flow rate of combustion air supplied to a gas turbine
is controlled through the opening of inlet guide vanes (IGVs) etc.
The opening of the IGVs is smaller during no load operation or
partial load operation of the gas turbine than during rated load
operation. Especially when the atmospheric temperature falls in
winter, an icing phenomenon of moisture in the air forming ice may
occur at the inlet part of the compressor. When the icing
phenomenon occurs, not only is the reliability of the gas turbine
adversely affected due to the resulting decrease in output and
efficiency of the gas turbine, but also the blades and vanes in a
front stage of the compressor may be damaged as the accumulated ice
falls away.
To avoid this phenomenon, there have been proposed various gas
turbines and operation methods thereof for anti-icing operation in
which the temperature of intake air entering the compressor is
raised. Patent Literature 1 shows one example of a bleed air
circulation method for anti-icing purposes, in which part of casing
air is extracted from a casing where air having been compressed in
the compressor and reached high temperature is stored, and that
part of casing air is circulated to an air intake facility on the
inlet side of the compressor to raise the temperature of air
entering the compressor and thereby prevent the icing
phenomenon.
Regarding a gas turbine that performs normal operation without
anti-icing operation, Patent Literature 2 shows one example of a
system and a method in which combustion in a gas turbine is
controlled on the basis of the turbine inlet temperature.
CITATION LIST
Patent Literature
Patent Literature 1: Japanese Patent Laid-Open No. H9-291833
Patent Literature 2: Japanese Patent No. 4119909
SUMMARY OF INVENTION
Technical Problem
When the operation of a gas turbine is switched from normal
operation to anti-icing operation based on the bleed air
circulation method, part of the casing air is extracted and
returned to the inlet side of the compressor. In this case, the
amount of air supplied to the combustor decreases, so that a shift
occurs in relations between the gas turbine output and control
variables and the combustion control becomes unstable, which may
have an adverse effect, such as generation of combustion
oscillation, on the gas turbine control.
In gas turbines intended for power generation, daily start and stop
(DSS) operation is performed to respond to variations in electric
power demand between the daytime and the nighttime. However,
repeatedly starting and stopping a gas turbine according to
variations in electric power demand is not desirable in terms of
the efficiency and the service life of the gas turbine. Therefore,
a device is desired that can widen the range of turndown (output
lower limit value) as much as possible and allows operation even at
a time of low electric power demand.
An object of the present invention is to provide a gas turbine
combustion control device that is capable of stable combustion
control even in the case of anti-icing operation and realizes
stable operation while meeting emission regulation values even
during turndown operation (partial load operation), and to further
provide a gas turbine combustion control method and a program
therefor.
Solution to Problem
(1) A gas turbine combustion control device according to a first
aspect of the present invention is a gas turbine combustion control
device that is installed in a gas turbine including: a compressor
having inlet guide vanes; a combustor having a plurality of fuel
nozzles; a turbine; a bleed air pipe through which bleed air from a
casing is returned to an inlet of an air intake facility; and an
air bleed valve that is mounted on the bleed air pipe and regulates
the amount of bleed air extracted, the gas turbine combustion
control device being configured to set fuel distribution ratios for
fuel circuits of fuel supplied to the combustor, and including: a
fuel distribution setting unit that sets a turbine inlet
temperature or a turbine inlet temperature-equivalent control
variable computed on the basis of input data, and sets the fuel
distribution ratios on the basis of the turbine inlet temperature
or the turbine inlet temperature-equivalent control variable; and a
valve opening setting unit that sets the valve openings of fuel
regulating valves provided in the fuel circuits on the basis of the
fuel distribution ratios, wherein the fuel distribution setting
unit includes correction means for modifying the fuel distribution
ratios on the basis of the amount of bleed air extracted.
(2) A gas turbine combustion control device according to a second
aspect of the present invention is the gas turbine combustion
control device according to (1), wherein the fuel distribution
setting unit includes: a turbine inlet temperature-equivalent
control variable setting section that calculates first interpolated
data equivalent to the turbine inlet temperature or the turbine
inlet temperature-equivalent control variable in a first operation
mode that is an operation mode in which the gas turbine does not
perform anti-icing operation, and second interpolated data
equivalent to the turbine inlet temperature or the turbine inlet
temperature-equivalent control variable in a second operation mode
that is an anti-icing operation mode in which a constant amount of
bleed air is set and part of the bleed air from the casing is
circulated to the air intake facility; and a fuel distribution
correction section that, using the first interpolated data and the
second interpolated data, modifies the fuel distribution ratios in
a predetermined operation mode on the basis of a specific parameter
determined by the amount of bleed air extracted in the
predetermined operation mode that is an anti-icing operation mode
in which an amount of bleed air required for stable combustion is
selected and that amount of bleed air is circulated to the air
intake facility.
(3) A gas turbine combustion control device according to a third
aspect of the present invention is the gas turbine combustion
control device according to (1), wherein the fuel distribution
setting unit includes: an interpolated output data calculation
section that calculates first interpolated output data related to
an output during no load operation in a first operation mode that
is an operation mode in which the gas turbine does not perform
anti-icing operation, and second interpolated output data related
to an output during rated load operation in the first operation
mode; an interpolated output data correction section that modifies
the first interpolated output data and the second interpolated
output data on the basis of a specific parameter determined by the
amount of bleed air extracted in a predetermined operation mode
that is an anti-icing operation mode in which an amount of bleed
air required for stable combustion is selected and that amount of
bleed air is circulated to the air intake facility; a control
variable calculation section that calculates a turbine inlet
temperature-equivalent control variable on the basis of the first
modified interpolated output data and the second modified
interpolated output data that have been modified; and a fuel
distribution calculation section that calculates the fuel
distribution ratios for the respective fuel circuits on the basis
of the turbine inlet temperature-equivalent control variable.
(4) A gas turbine combustion control device according to a fourth
aspect of the present invention is the gas turbine combustion
control device according to (3), wherein the interpolated output
data correction section includes: a correction factor calculation
section that calculates an output correction factor that varies
according to the specific parameter; and an interpolated output
data modification section that modifies the first interpolated
output data and the second interpolated output data using the
output correction factor.
(5) A gas turbine combustion control device according to a fifth
aspect of the present invention is the gas turbine combustion
control device according to (2), wherein the fuel distribution
correction section includes: a control variable interpolation
section that, using the first interpolated data and the second
interpolated data, calculates a modified turbine inlet
temperature-equivalent control variable in the predetermined
operation mode on the basis of the specific parameter; and a fuel
distribution calculation section that calculates the fuel
distribution ratios for the respective fuel circuits on the basis
of the modified turbine inlet temperature-equivalent control
variable.
(6) A gas turbine combustion control device according to a sixth
aspect of the present invention is the gas turbine combustion
control device according to (2) or (5), wherein the turbine inlet
temperature-equivalent control variable setting section includes:
means for calculating first interpolated output data related to an
output during no load operation in the first operation mode and
second interpolated output data related to an output during rated
load operation in the first operation mode; means for calculating
first interpolated data equivalent to the turbine inlet
temperature-equivalent control variable in the first operation mode
using the first interpolated output data and the second
interpolated output data; means for calculating third interpolated
output data related to an output during no load operation in the
second operation mode and fourth interpolated output data related
to an output during rated load operation in the second operation
mode; and means for calculating second interpolated data equivalent
to the turbine inlet temperature-equivalent control variable in the
second operation mode using the third interpolated output data and
the fourth interpolated output data.
(7) A gas turbine combustion control method according to a seventh
aspect of the present invention is a gas turbine combustion control
method for a gas turbine including: a compressor having inlet guide
vanes; a combustor having a plurality of fuel nozzles; a turbine; a
bleed air pipe through which bleed air from a casing is returned to
an inlet of an air intake facility; an air bleed valve that is
mounted on the bleed air pipe and regulates the amount of bleed air
extracted; and a gas turbine combustion control device configured
to set fuel distribution ratios for circuits of fuel supplied to
the combustor, the gas turbine combustion control method including
the steps of: calculating first interpolated data equivalent to a
turbine inlet temperature or a turbine inlet temperature-equivalent
control variable in a first operation mode computed on the basis of
input data on the first operation mode that is an operation mode in
which the gas turbine does not perform anti-icing operation;
calculating second interpolated data equivalent to a turbine inlet
temperature or a turbine inlet temperature-equivalent control
variable in a second operation mode computed on the basis of input
data on the second operation mode that is an anti-icing operation
mode in which a constant amount of bleed air is set and part of the
bleed air from the casing is circulated to the air intake facility;
using the first interpolated data and the second interpolated data,
calculating a modified turbine inlet temperature or a modified
turbine inlet temperature-equivalent control variable in a
predetermined operation mode on the basis of a specific parameter
determined by the amount of bleed air extracted in the
predetermined operation mode that is an anti-icing operation mode
in which an amount of bleed air required for stable combustion is
selected and that amount of bleed air is circulated to the air
intake facility; calculating the fuel distribution ratios for the
respective fuel circuits in the predetermined operation mode on the
basis of the modified turbine inlet temperature or the modified
turbine inlet temperature-equivalent control variable; and setting
valve openings for the respective fuel circuits on the basis of the
fuel distribution ratios.
(8) A gas turbine combustion control method according to an eighth
aspect of the present invention is a gas turbine combustion control
method for a gas turbine including: a compressor having inlet guide
vanes; a combustor having a plurality of fuel nozzles; a turbine; a
bleed air pipe through which bleed air from a casing is returned to
an inlet of an air intake facility; an air bleed valve that is
mounted on the bleed air pipe and regulates the amount of bleed air
extracted; and a gas turbine combustion control device configured
to set fuel distribution ratios for circuits of fuel supplied to
the combustor, the gas turbine combustion control method including
the steps of: calculating first interpolated output data
corresponding to a turbine inlet temperature related to an output
during no load operation on the basis of input data on a first
operation mode that is an operation mode in which the gas turbine
does not perform anti-icing operation; calculating second
interpolated output data corresponding to a turbine inlet
temperature related to an output during rated load operation on the
basis of input data on the first operation mode; calculating an
output correction factor on the basis of a specific parameter
determined by the amount of bleed air extracted in a predetermined
operation mode that is an anti-icing operation mode in which an
amount of bleed air required for stable combustion is selected and
that amount of bleed air is circulated to the air intake facility;
calculating first modified interpolated output data by modifying
the first interpolated output data on the basis of the output
correction factor; calculating second modified interpolated output
data by modifying the second interpolated output data on the basis
of the output correction factor; using the first modified
interpolated output data and the second modified interpolated
output data, calculating a turbine inlet temperature-equivalent
control variable on the basis of a turbine output in the
predetermined operation mode; calculating the fuel distribution
ratios for the respective fuel circuits in the predetermined
operation mode on the basis of the turbine inlet
temperature-equivalent control variable; and setting valve openings
for the respective fuel circuits on the basis of the fuel
distribution ratios.
(9) A gas turbine combustion control method according to a ninth
aspect of the present invention is a gas turbine combustion control
method for a gas turbine including: a compressor having inlet guide
vanes; a combustor having a plurality of fuel nozzles; a turbine; a
bleed air pipe through which bleed air from a casing is returned to
an inlet of an air intake facility; an air bleed valve that is
mounted on the bleed air pipe and regulates the amount of bleed air
extracted; and a gas turbine combustion control device configured
to set fuel distribution ratios for circuits of fuel supplied to
the combustor, the gas turbine combustion control method including
the steps of: creating a database on the basis of input data on a
first operation mode that is an operation mode in which the gas
turbine does not perform anti-icing operation, and a database on
the basis of input data on a second operation mode that is an
anti-icing operation mode in which a constant amount of bleed air
is set and part of the bleed air from the casing is circulated to
the air intake facility; calculating first interpolated data
equivalent to a turbine inlet temperature or a turbine inlet
temperature-equivalent control variable in the first operation mode
on the basis of the database; calculating second interpolated data
equivalent to a turbine inlet temperature or a turbine inlet
temperature-equivalent control variable in the second operation
mode on the basis of the database; using the first interpolated
data and the second interpolated data, calculating a modified
turbine inlet temperature or a modified turbine inlet
temperature-equivalent control variable in a predetermined
operation mode on the basis of a specific parameter determined by
the amount of bleed air extracted in the predetermined operation
mode that is an anti-icing operation mode in which an amount of
bleed air required for stable combustion is selected and that
amount of bleed air is circulated to the air intake facility;
calculating the fuel distribution ratios for the respective fuel
circuits in the predetermined operation mode on the basis of the
modified turbine inlet temperature or the modified turbine inlet
temperature-equivalent control variable; and setting valve openings
for the respective fuel circuits on the basis of the fuel
distribution ratios.
(10) A gas turbine combustion control device according to a tenth
aspect of the present invention is the gas turbine combustion
control device according to any one of (2) to (5), wherein the
specific parameter is one of an intake air temperature difference,
a casing pressure ratio, the amount of bleed air, and the valve
opening of the air bleed valve.
(11) A gas turbine combustion control method according to an
eleventh aspect of the present invention is the gas turbine
combustion control method according to any one of (7) to (9),
wherein the specific parameter is one of an intake air temperature
difference, a casing pressure ratio, the amount of bleed air, and
the valve opening of the air bleed valve.
(12) A program according to a twelfth aspect of the present
invention is a program that executes the gas turbine combustion
control method.
Advantageous Effects of Invention
According to the above-described gas turbine combustion control
device and combustion control method and program therefor, even
when normal operation is switched to anti-icing operation, stable
combustion control of the combustors is maintained, so that an
increase in NO etc. can be avoided and generation of combustion
oscillation can be suppressed. As a result, stable operation of the
gas turbine is realized. Moreover, it is possible to realize stable
operation while meeting emission regulation values even during
turndown operation (partial load operation).
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a view showing the schematic device configuration of a
gas turbine in one embodiment according to the present
invention.
FIG. 2 is a view showing the device configuration of a combustion
control device according to Embodiment 1 and data handled by the
combustion control device.
FIG. 3 is a view showing one example of a database according to
Embodiment 1.
FIG. 4 is a view showing a relation between an output correction
factor and an intake air temperature difference according to
Embodiment 1.
FIG. 5 is a view showing a relation between a pilot ratio and a
turbine inlet temperature-equivalent control variable according to
Embodiment 1.
FIG. 6 is a view showing a control logic of the combustion control
device according to Embodiment 1.
FIG. 7 is a view showing a control logic according to Modified
Example 1.
FIG. 8 is a view showing a control logic according to Modified
Example 2.
FIG. 9 is a view showing the process flow of a control method
according to Embodiment 1.
FIG. 10 is a view showing the device configuration of a combustion
control device according to Embodiment 2 and data handled by the
combustion control device.
FIG. 11 is a view showing a relation between a turbine inlet
temperature-equivalent control variable (CLCSO) and a casing
pressure ratio in operation modes according to Embodiment 2.
FIG. 12 is a view showing the process flow of a control method
according to Embodiment 2.
FIG. 13 is a view showing the device configuration of a combustion
control device according to Embodiment 3 and data handled by the
combustion control device.
FIG. 14 is a view showing the process flow of a control method
according to Embodiment 3.
DESCRIPTION OF EMBODIMENTS
In the following, various embodiments of gas turbine combustion
control device and combustion control method for a gas turbine
intended for anti-icing operation will be described with reference
to the drawings.
In the embodiments to be described below, three operation modes, a
first operation mode, a second operation mode, and a predetermined
operation mode, are distinguished from one another according to
differences in operation conditions of a gas turbine. The first
operation mode refers to an operation mode of normal operation in
which the gas turbine does not perform anti-icing operation. The
second operation mode refers to a standard operation mode of
anti-icing operation in which a constant amount of bleed air is set
and part of casing air is circulated to an air intake facility. The
predetermined operation mode refers to an operation mode of
anti-icing operation in which an amount of bleed air required for
stable combustion is selected on the basis of the operation status
of the gas turbine and that amount of bleed air is circulated to
the air intake facility, and in which optimal operation conditions
for anti-icing operation are set.
Embodiment 1
Gas turbine combustion control device and combustion control method
of Embodiment 1 according to the present invention will be
described with reference to FIG. 1 to FIG. 9.
FIG. 1 shows the device configuration of a gas turbine of
Embodiment 1. A gas turbine 1 is composed mainly of a compressor 2,
combustors 3, a turbine 4, and a combustion control device 50, and
electric power is taken out by a generator 5 connected to a
rotating shaft 8.
The compressor 2 pressurizes and compresses atmospheric air A taken
in through an air intake facility 7, and temporarily stores the
compressed air A in a casing 6 of the compressor 2. The combustor 3
mixes a fuel G and the compressed air A supplied from the casing 6
and combusts the mixture to produce high-temperature combustion
gas. The turbine 4 has a configuration in which multiple stages of
blades fixed to the rotating shaft 8 and multiple stages of vanes
supported on the casing are alternately disposed. The turbine 4
introduces the combustion gas generated in the combustors 3 to
rotate the rotating shaft 8, and converts the thermal energy into
rotary energy to drive the generator 5. The combustion gas
discharged from the turbine 4 is discharged as waste gas WG through
an exhaust diffuser (not shown) from an exhaust duct 13 to the
outside of the system.
The air intake facility 7 including a filter is provided on the
upstream side of the compressor 2. An air intake duct 11 with a
built-in intake air filter (not shown) constitutes the air intake
facility 7. The air intake duct 11 is provided with an intake air
temperature indicator 34, and an intake air temperature 61c is
measured and output to the combustion control device 50.
The compressor 2 further has a bleed air pipe 12 through which part
of the pressurized casing air inside the casing 6 is extracted and
returned to the inlet side of the air intake facility 7. The bleed
air pipe 12 has a bleed air flowmeter 36 that measures an amount of
bleed air 61i (FIG. 8) and an air bleed valve 22. The measured
amount of bleed air 61i is output to the combustion control device
50. The air bleed valve 22 is controlled to be turned on and off
through an air bleed valve opening command value that is output
from an air bleed valve opening setting section 83 of the
combustion control device 50. The compressor 2 is provided with
inlet guide vanes (IGVs) 20 on the inlet side. The inlet guide
vanes (IGVs) 20 are variable vanes that regulate the amount of air
flowing into the compressor 2 according to the gas turbine load. An
IGV opening command value is output from an IGV opening setting
section 82 of the combustion control device 50, and the IGVs are
controlled by an IGV driving unit 21. A casing pressure indicator
31 and a casing temperature indicator 30 are provided inside the
casing 6, and a casing pressure 61p (FIG. 7) and a casing
temperature measured are output to the combustion control device
50. The load on the gas turbine 1 is output as a load value from a
generator output detection unit 40 of the generator 5 to the
combustion control device 50.
The combustor 3 has a plurality of types of fuel nozzles, namely, a
pilot nozzle 15 and main nozzles 16. The pilot nozzle 15 is a
diffusion combustion nozzle for stabilizing combustion inside the
combustor. A plurality of premixing fuel nozzles disposed around
the pilot nozzle 15 are used as the main nozzles 16. To achieve NO
reduction, a top-hat nozzle (not shown) may be further provided as
one of the plurality of types of fuel nozzles.
Fuel circuits that supply the fuel G to the pilot nozzle 15 and the
main nozzles 16 have a first fuel circuit 18 and a second fuel
circuit 19. The first fuel circuit 18 and the second fuel circuit
19 are branch pipes that are branched from a fuel main circuit 17
and connected to the respective nozzles. The first fuel circuit 18
is a pipe that is branched from the fuel main circuit 17 and
supplies the fuel G to the pilot nozzle 15, and is provided with a
pilot fuel regulating valve 23. The second fuel circuit 19 is a
pipe that supplies the fuel G to the main nozzles 16, and is
provided with a main fuel regulating valve 24. The fuel main
circuit 17 is provided with a fuel flowmeter 37 and a fuel
temperature indicator 38, and the measurement values are output to
the combustion control device 50. The pilot fuel regulating valve
23 regulates the flow rate of pilot fuel supplied to the pilot
nozzle 15 according to a valve opening command value output from a
fuel valve opening setting section 81 of the combustion control
device 50. Similarly, the main fuel regulating valve 24 regulates
the flow rate of fuel supplied to the main nozzles 16 according to
a valve opening command value output from the fuel valve opening
setting section 81 of the combustion control device 50.
To discharge the compressed air A from inside the casing 6 to the
exhaust duct 13 for the purpose of, for example, adjusting the
properties of the waste gas WG during partial load operation of the
gas turbine, the casing 6 is provided with a turbine bypass pipe 14
that connects the casing 6 and the exhaust duct 13 to each other so
as to bypass the combustors 3 and the turbine 4. The turbine bypass
pipe 14 is provided with a turbine bypass valve 25 that regulates
the amount of bypassing compressed air A according to a turbine
bypass valve opening command value from a turbine bypass valve
opening setting section 84 of the combustion control device 50.
The temperature of the waste gas WG discharged from the gas turbine
1 is measured by a waste gas temperature indicator 39 and the
measurement value is output to the combustion control device 50. An
atmospheric pressure indicator 33 and an atmospheric temperature
indicator 32 that measure an atmospheric pressure 61k and an
atmospheric temperature 61g (FIG. 6) are disposed on the outside,
and the measurement values are output to the combustion control
device 50. Moreover, an anti-icing command value (AID) that is one
of external command values and specifies the gas turbine load and
commands to turn on or off anti-icing operation (to put the gas
turbine into and out of anti-icing operation) is output from the
outside to the combustion control device 50.
The combustion control device 50 is composed of an input unit 60
that receives input signals from the measurement instruments and
the external command values, a fuel distribution setting unit 70
that computes a turbine inlet temperature on the basis of the input
signals or the external command values and determines a required
fuel flow rate, and a valve opening setting unit 80 that sets the
valve openings of the valves on the basis of the command values
output from the fuel distribution setting unit 70. The combustion
control device 50 has a computer in its configuration. The
functional components of the combustion control device 50 function
through execution of a program installed in an external memory of
the computer etc.
The valve opening setting unit 80 is composed of the fuel valve
opening setting section 81 that sets the openings of the pilot fuel
regulating valve 23 and the main fuel regulating valve 24, the IGV
opening setting section 82 that sets the opening of the inlet guide
vanes (IGVs) 20, the air bleed valve opening setting section 83
that sets the opening of the air bleed valve 22, and the turbine
bypass valve opening setting section 84 that sets the opening of
the turbine bypass valve.
The input data 61 (FIG. 2) sent from the measurement instruments or
the outside to the input unit 60 include a generator output, fuel
flow rate, combustion air flow rate, bleed air flow rate, intake
air flow rate, turbine bypass flow rate, IGV opening, air bleed
valve opening, turbine bypass valve opening, waste gas temperature,
intake air temperature, atmospheric temperature, casing
temperature, casing pressure, intake air pressure, atmospheric
pressure, and turbine output command value (MW) as well as
anti-icing command value (AID) as external command values. These
input signals are output to the fuel distribution setting unit
70.
The fuel distribution setting unit 70 computes the combustion
temperature in the combustor 3, i.e., a turbine inlet temperature
(TIT), on the basis of the measurement values, such as flow rates,
temperatures, and pressures at various parts, that show the
operation state of the gas turbine, and the gas turbine output
command value (MW) as well as the anti-icing command value (AID),
from the input unit 60, and sets a dimensionless (computed) turbine
inlet temperature-equivalent control variable (CLCSO) on the basis
of the turbine inlet temperature (TIT). The turbine inlet
temperature-equivalent control variable (CLCSO) is proportional to
the turbine inlet temperature (TIT). If the IGV opening is
constant, the turbine inlet temperature (TIT) is proportional to
the turbine output (generator output). Fuel distribution ratios
FDRs of the fuel supplied to the various fuel nozzles are
determined as a function of the turbine inlet
temperature-equivalent control variable (CLCSO). The fuel
distribution ratios FDRs for the pilot fuel regulating valve 23 and
the main fuel regulating valve 24 set in the fuel distribution
setting unit 70 are output to the valve opening setting unit
80.
Although not shown, the total flow rate of the fuel supplied to the
various fuel nozzles is determined by a total fuel flow rate
command value (CSO) that is set from the turbine output command
value (MW), the generator output, etc., and the fuel distribution
ratios FDRs for the pilot fuel regulating valve 23 and the main
fuel regulating valve 24 are determined from the turbine inlet
temperature-equivalent control variable (CLCSO).
In the fuel valve opening setting section 81, the fuel flow rates
for the respective pilot fuel regulating valve 23 and main fuel
regulating valve 24 are calculated on the basis of the total fuel
flow rate command value (CSO) and the fuel distribution ratios FDRs
for the valves, and the Cv values of the pilot fuel regulating
valve 23 and the main fuel regulating valve 24 are calculated and
the valve openings thereof are set. The valve opening command
values are output to the fuel regulating valves to control the flow
rate of the fuel supplied to each fuel nozzle. The IGV opening
setting section 82 sets the IGV opening on the basis of a generator
output 61a, and outputs the IGV opening to the IGV driving unit 21.
The air bleed valve opening setting section 83 sets the air bleed
valve opening on the basis of the anti-icing command value (AID)
and outputs the air bleed valve opening to the air bleed valve 22.
The turbine bypass valve opening setting section 84 sets the valve
opening on the basis of the turbine bypass valve opening command
value, and outputs the valve opening to the turbine bypass valve
25.
Next, the configuration of the combustion control device according
to this embodiment and data handled in each unit of the combustion
control device will be described with reference to FIG. 2. For
convenience, among the sections of the valve opening setting unit
80 of the combustion control device 50, only the fuel valve opening
setting section 81 is shown in FIG. 2.
In this embodiment, a database 70a is created with reference to the
first operation mode in which anti-icing operation is not
performed. Specifically, control parameters are selected from the
input data 61 on the various measurement values, the external
command values, and the various control values that is received by
the input unit 60 and shows the operation state of the gas turbine
related to the first operation mode, and relations between the
control parameters and the turbine output (generator output MW) are
established as the database 70a on the basis of the input data 61
and a data group of separately accumulated various measurement
values. In this embodiment, the turbine inlet
temperature-equivalent control variable (CLCSO) is set on the basis
of the database 70a. As the control parameters, the generator
output 61a, an IGV opening 61b, the intake air temperature 61c, an
intake air flow rate 61d, and a turbine bypass flow rate 61e are
selected. The parameters presented herein as the control parameters
are mere examples, to which the control parameters are not
limited.
FIG. 3 shows one example of the database 70a. FIG. 3 is an example
in which the generator output (MW) is represented on the vertical
axis and the intake air temperature (TIN) selected from the control
parameters is represented on the horizontal axis. The solid lines
indicate the relation between the generator output (MW) and the
intake air temperature (TIN) at the turbine inlet temperature (TIT)
during rated load operation, while the dashed lines indicate the
relation between the generator output (MW) and the intake air
temperature (TIN) at the turbine inlet temperature (TIT) during no
load operation. For the IGV opening, the opening in three stages,
0%, 50%, and 100%, are shown. According to FIG. 3, if the intake
air temperature and the IGV opening are constant, the generator
output (MW) and the turbine inlet temperature (TIT) are
proportional to each other. Moreover, as the intake air temperature
(TIN) rises, the generator output (MW) decreases. If the intake air
temperature (TIN) is constant, the generator output (MW) increases
with the increasing IGV opening.
Although not shown in FIG. 3, the relations between the generator
output (MW) and the intake air flow rate and the turbine bypass
flow rate are also included in the database 70a.
Here, the turbine inlet temperature-equivalent control variable
(CLCSO) corresponding to the generator output 61a can be calculated
by calculating a generator output during no load operation in the
first operation mode (first interpolated output data 71a) and a
generator output during rated load operation in the first operation
mode (second interpolated output data 71b) from the database 70a
and interpolating both pieces of data with the actual generator
output 61a during actual operation. This calculation method is
shown in Patent Literature 2 etc. The expression "during no load
operation" refers to a case where the turbine inlet temperature is
700.degree. C., for example, and the expression "during rated load
operation" refers to a case where the turbine inlet temperature is
1500.degree. C., for example.
With the case of the intake air temperature (TIN) and the IGV
opening of 100% shown in FIG. 3 taken as an example, the
calculation method of the turbine inlet temperature-equivalent
control variable (CLCSO) will be described.
The turbine inlet temperature-equivalent control variable (CLCSO)
is the generator output during actual operation shown in percent
(%), on the basis of CLCSO=100% at a generator output during rated
load operation YMW and CLCSO=0 (zero) % at a generator output
during no load operation XMW. That is, when the generator output
61a during actual operation input into the input unit 60 is AMW,
the relation between the generator output and CLCSO is expressed by
the following formula (1): CLCSO=(AMW-XMW)/(YMW-XMW).times.100
(1)
In FIG. 3, the line L1 indicates the relation between the generator
output (MW) and the intake air temperature (TIN) in the case of no
load operation at the IGV opening of 100%, and the line L2
indicates the relation in the case of rated load operation at the
IGV opening of 100%. The point on the line L1 corresponding to the
intake air temperature (TIN) is referred to as a point X1, and the
generator output at the point X1 is denoted by XMW. Similarly, the
point on the line L2 corresponding to the intake air temperature
(TIN) is referred to as a point Y1, and the generator output at the
point Y1 is denoted by YMW. The point on the line segment X1Y1
corresponding to the generator output during actual operation AMW
is referred to as a point Z1.
In this case, the turbine inlet temperature-equivalent control
variable (CLCSO) during actual operation is equivalent to a value
of the ratio (line segment Z1X1)/(line segment Y1X1) shown in
percent (%). That is, the turbine inlet temperature-equivalent
control variable (CLCSO) during actual operation can be calculated
as shown in the above formula (1) by interpolating the output
during rated load operation YMW and the output during no load
operation XMW with the output during actual operation AMW.
Specifically, in FIG. 3, CLCSO during actual operation can be
calculated by varying the intake air temperature (TIN) and the IGV
opening and selecting a value corresponding to the output during
actual operation (AMW). The dot-and-dash line indicates, for
reference, an estimated relation between the generator output (MW)
and the intake air temperature (TIN) at a predetermined turbine
inlet temperature during actual operation at the IGV opening of
100% on the assumption of the predetermined operation mode. While
the method of calculating the turbine inlet temperature-equivalent
control variable (CLCSO) at specific intake air temperature and IGV
opening has been described above, the turbine inlet
temperature-equivalent control variable (CLCSO) can be calculated
by the same method when other intake air temperatures and IGV
opening are selected. Although the turbine inlet temperatures
during rated load operation and no load operation have been used,
these temperatures are mere examples, to which the turbine inlet
temperatures are not limited.
As shown in FIG. 2, the fuel distribution setting unit 70 in this
embodiment includes an interpolated output data calculation section
71, an interpolated output data correction section 72, a control
variable calculation section 75, and a fuel distribution
calculation section 76.
As described above, when the gas turbine 1 is put into anti-icing
operation, the bleed air, which is part of the casing air
extracted, is circulated through the bleed air pipe 12 to the air
intake facility 7. As a result, despite the same IGV opening, the
amount of air supplied to the combustors decreases by the amount of
bleed air circulated in anti-icing operation, and thus the gas
turbine is actually in an operation state with the IGVs further
closed. In this case, the combustion control becomes unstable as a
difference occurs between the turbine inlet temperature-equivalent
control variable (CLCSO) calculated from the IGV opening, the
generator output, etc. and the actual turbine inlet temperature. To
remedy this problem, it is necessary to modify the relation between
the generator output and the control variable during normal
operation that is the first operation mode, and correct the
operation conditions so as to be suitable for anti-icing operation.
Whether or not to start anti-icing operation is determined
according to the atmospheric temperature 61g, and when the
atmospheric temperature 61g becomes equal to or lower than a
predetermined value, the anti-icing external command value (AID) is
input from the outside into the combustion control device 50.
The interpolated output data calculation section 71 is a section
that prepares for the correction of the operation conditions. The
interpolated output data calculation section 71 calculates the
turbine output (generator output) during no load operation of the
gas turbine as the first interpolated output data 71a, and
calculates the turbine output (generator output) during rated load
operation of the gas turbine as the second interpolated output data
71b, and outputs both pieces of data to the interpolated output
data correction section 72.
The interpolated output data correction section 72 is composed of a
correction factor calculation section 73 and an interpolated output
data modification section 74. A specific parameter that affects the
stability of the combustion control during anti-icing operation is
selected in advance. The interpolated output data correction
section 72 functions to set first modified interpolated output data
74a and second modified interpolated output data 74b by modifying
the first interpolated output data 71a and the second interpolated
output data 71b on the basis of the selected specific
parameter.
The correction factor calculation section 73 functions to select an
output correction factor F for the specific parameter for the
purpose of modifying the first interpolated output data 71a and the
second interpolated output data 71b transmitted from the
interpolated output data calculation section 71. In anti-icing
operation, the stability of the combustion control depends on the
amount of bleed air. Therefore, other than an intake air
temperature difference 61f and a casing pressure ratio 61h that are
significantly affected by the amount of bleed air, a valve opening
61m of the air bleed valve and the amount of bleed air 61i can also
be selected as the specific parameter. The intake air temperature
difference 61f refers to the difference between the intake air
temperature 61c on the inlet side of the air intake facility 7 and
the atmospheric temperature 61g. The casing pressure ratio 61h
refers to the ratio of the casing pressure 61p to the atmospheric
pressure 61k (casing pressure 61p/atmospheric pressure 61k).
In this embodiment, the intake air temperature difference 61f is
taken as a typical example of the specific parameter. FIG. 4 shows
a relation between the intake air temperature difference (.DELTA.T)
represented on the horizontal axis and the output correction factor
F represented on the vertical axis. In the air intake facility 7,
the bleed air at a comparatively high temperature is mixed with
atmospheric air taken in from the outside, so that the intake air
temperature difference (.DELTA.T) increases as the amount of bleed
air increases. The output correction factor F tends to decrease as
the intake air temperature difference (.DELTA.T) increases. During
normal operation (first operation mode) in which no bleed air is
circulated, the intake air temperature difference (AT) is zero and
the output correction factor F is 1.0. Although not shown, the
output correction factor F exhibits almost the same tendency in the
case of other specific parameters (the casing pressure ratio, the
valve opening of the air bleed valve, and the amount of bleed air).
The calculated output correction factor F is output to the
interpolated output data modification section 74.
The interpolated output data modification section 74 functions to
calculate the first modified interpolated output data 74a and the
second modified interpolated output data 74b by modifying the first
interpolated output data 71a and the second interpolated output
data 71b on the basis of the output correction factor F selected in
the correction factor calculation section 73. Specifically, the
first modified interpolated output data 74a is calculated by
multiplying the first interpolated output data 71a by the output
correction factor F. Similarly, the second modified interpolated
output data 74b is calculated by multiplying the second
interpolated output data 71b by the output correction factor F. The
first modified interpolated output data 74a and the second modified
interpolated output data 74b are output to the control variable
calculation section 75.
The control variable calculation section 75 functions to calculate
the turbine inlet temperature-equivalent control variable (CLCSO)
using the first modified interpolated output data 74a and the
second modified interpolated output data 74b that have been
corrected with the intake air temperature difference 61f.
Specifically, using the first modified interpolated output data 74a
corresponding to the output during no load operation and the second
modified interpolated output data 74b corresponding to the output
during rated load operation, instead of the first interpolated
output data 71a and the second interpolated output data 71b
described above, the control variable calculation section 75
calculates the turbine inlet temperature-equivalent control
variable (CLCSO) by the above formula (1) through interpolation
with the turbine output (generator output MW) 61a during actual
operation. The calculated turbine inlet temperature-equivalent
control variable (CLCSO) is output to the fuel distribution
calculation section 76.
The fuel distribution calculation section 76 functions to set the
fuel distribution to the fuel nozzles on the basis of the turbine
inlet temperature-equivalent control variable (CLCSO). FIG. 5 shows
a relation between a pilot ratio PR and the turbine inlet
temperature-equivalent control variable (CLCSO). The pilot ratio PR
can be determined on the basis of the turbine inlet
temperature-equivalent control variable (CLCSO) calculated in the
control variable calculation section 75. Specifically, the pilot
ratio PR is the fuel distribution ratio FDR, shown in percent (%),
relative to the total flow rate of the fuel supplied to the first
fuel circuit 18 connected to the pilot nozzle 15, and a main ratio
MR is a value obtained by subtracting the pilot ratio PR from the
total fuel flow rate, i.e., a ratio relative to the total fuel flow
rate, shown in percent (%). That is, the main ratio MR refers to
the fuel distribution ratio FDR for the second fuel circuit 19
connected to the main nozzles 16. The fuel distribution ratios FDRs
for the respective first fuel circuit 18 and second fuel circuit 19
determined in the fuel distribution calculation section 76 are
output to the fuel valve opening setting section 81.
The fuel valve opening setting section 81 of the valve opening
setting unit 80 functions to set the valve openings of the fuel
regulating valves on the basis of the fuel distribution ratios FDRs
transmitted from the fuel distribution calculation section 76 and
the total fuel flow rate command value (CSO) separately set in the
fuel distribution setting unit 70. Specifically, for the pilot fuel
regulating valve 23, the fuel valve opening setting section 81
calculates the flow rate of the fuel supplied to the pilot nozzle
15 on the basis of the total fuel flow rate command value (CSO) and
the fuel distribution ratio FDR for the first fuel circuit 18, and
calculates the Cv value of the pilot fuel regulating valve 23 and
sets the valve opening thereof. Similarly, for the main fuel
regulating valve 24, the valve opening can be set from the total
fuel flow rate command value (CSO) and the fuel distribution ratio
FDR for the second fuel circuit 19. A valve opening command value
PVS for the pilot fuel regulating valve 23 and a valve opening
command value MVS for the main fuel regulating valve 24 set in the
valve opening setting unit 80 are output to the pilot fuel
regulating valve 23 and the main fuel regulating valve 24,
respectively. When a top-hat nozzle (not shown) is used, the valve
opening of a top-hat fuel regulating valve (not shown) can be set,
as with the pilot nozzle, from a relation between a top-hat ratio
and the turbine inlet temperature-equivalent control variable
(CLCSO).
Next, a control logic of the combustion control device of this
embodiment will be described using FIG. 6. The control logic shown
in FIG. 6 is based on the control logic for calculating CLCSO shown
in Patent Literature 2, with a logic for correcting the output on
the basis of the output correction factor F added thereto. First,
anti-icing operation of the gas turbine is started upon receipt of
the anti-icing command value (AID), and correction work of the
turbine inlet temperature-equivalent control variable (CLCSO) is
started. This embodiment is an example in which the intake air
temperature difference 61f is used as the specific parameter.
Specifically, in the method of this embodiment, the turbine inlet
temperature-equivalent control variable (CLCSO) is calculated as
described above by correcting the first interpolated output data
71a on no load operation and the second interpolated output data
71b on rated load operation with the output correction factor F.
The part of the control logic modified from the control logic of
the conventional example of Patent Literature 2 etc. is shown in
the area enclosed by the thick solid line.
In the control logic shown in FIG. 6, when the gas turbine is put
into anti-icing operation, a turn-on signal of the anti-icing
command value (AID) is multiplied by a multiplier 115. Meanwhile,
on the basis of the intake air temperature 61c and the atmospheric
temperature 61g, the intake air temperature difference 61f is
calculated by a subtracter 114 by subtracting the atmospheric
temperature 61g from the intake air temperature 61c. Next, the
output correction factor F is calculated by a function generator
116 on the basis of the intake air temperature difference 61f.
Meanwhile, as described above, the first interpolated output data
71a related to the output during no load operation and the second
interpolated output data 71b related to the output during rated
load operation are generated by a first function generator 111 and
a second function generator 112 on the basis of the database 70a
that summarizes the relations between the control parameters and
the generator output (MW). Next, the corrected first modified
interpolated output data 74a is calculated by a multiplier 118 by
multiplying the calculated first interpolated output data 71a by
the output correction factor F. Similarly, the corrected second
modified interpolated output data 74b is calculated by a multiplier
121 by multiplying the second interpolated output data 71b by the
output correction factor F. Next, the turbine inlet
temperature-equivalent control variable (CLCSO) is calculated on
the basis of the first modified interpolated output data 74a and
the second modified interpolated output data 74b. For the specific
calculation method, the turbine inlet temperature-equivalent
control variable (CLCSO) can be calculated on the basis of the
above formula (1), and the specific procedure is described in
Patent Literature 2 etc.
FIG. 7 shows Modified Example 1 of the control logic shown in FIG.
6. Modified Example 1 is an example in which the casing pressure
ratio is used as the specific parameter. Specifically, when the gas
turbine is put into anti-icing operation, a turn-on signal of the
anti-icing command value (AID) is multiplied by a multiplier 132.
Meanwhile, the casing pressure ratio 61h (casing pressure
61p/atmospheric pressure 61k) is calculated by a divider 131 from
the casing pressure 61p and the atmospheric pressure 61k. Next, the
output correction factor F is calculated by a function generator
133. Then, the first interpolated output data 71a and the second
interpolated output data 71b are multiplied by the calculated
output correction factor F by multipliers 134, 135. The subsequent
method of calculating the turbine inlet temperature-equivalent
control variable (CLCSO) is the same as that of Patent Literature 2
etc.
The part other than the control logic enclosed by the thick line
has the same configuration as in Embodiment 1, and therefore the
same names and reference signs are used and detailed description
thereof is omitted.
FIG. 8 shows Modified Example 2 in which the amount of bleed air
61i or the air bleed valve opening 61m is selected as the specific
parameter. When the gas turbine is put into anti-icing operation, a
turn-on signal of the anti-icing command value (AID) is multiplied
by a multiplier 141. Meanwhile, the output correction factor F is
calculated by a function generator 142 from the amount of bleed air
61i or the air bleed valve opening 61m. The first interpolated
output data 71a and the second interpolated output data 71b are
each multiplied by the calculated output correction factor F by
multipliers 143, 144. The subsequent method of calculating the
turbine inlet temperature-equivalent control variable (CLCSO) is
the same as the method described in Patent Literature 2 etc. The
part other than the control logic enclosed by the thick line has
the same configuration as in Embodiment 1, and therefore the same
names and reference signs are used and detailed description thereof
is omitted.
Next, regarding the combustion control method that is applied when
anti-icing operation of the gas turbine is started, the process
flow of the control method according to Embodiment 1 will be
described on the basis of FIG. 9. The basic concept of the process
flow of the control method according to Embodiment 1 is based on
the method described in Patent Literature 2 that shows the process
flow related to a combustion control method during normal operation
(first operation mode). Processing tasks that are different from
those of the method described in Patent Literature 2 are indicated
as thick-lined blocks in FIG. 9.
The measurement values, the various valve openings, and the
external command values are transmitted to the input unit 60, and
output as the input data 61 to the fuel distribution setting unit
70 (SP1).
Next, as a preparatory processing task, the database 70a is created
of the relations between the control parameters and the turbine
output (generator output MW) in the fuel distribution setting unit
70 on the basis of the input data 61 received by the input unit 60
(SP2).
On the basis of the created database 70a, the first interpolated
output data 71a on no load operation and the second interpolated
output data 71b on rated load operation are calculated in the
interpolated output data calculation section 71 (SP3, SP4).
In the correction factor calculation section 73, the intake air
temperature difference 61f is calculated on the basis of the intake
air temperature 61c and the atmospheric temperature 61g transmitted
from the input unit 60, and the output correction factor F is
calculated on the basis of the calculated intake air temperature
difference 61f (SP5).
When the specific parameter is the casing pressure ratio 61h as
described above, the casing pressure ratio 61h is calculated from
the casing pressure 61p and the atmospheric pressure 61k, instead
of the intake air temperature 61c and the atmospheric temperature
61g, and the output correction factor F is calculated. When the
specific parameter is the amount of bleed air 61i or the air bleed
valve opening 61m, the output correction factor F is calculated
from the amount of bleed air 61i or the air bleed valve opening
61m.
In the interpolated output data modification section 74, the first
modified interpolated output data 74a and the second modified
interpolated output data 74b are calculated by multiplying the
first interpolated output data 71a and the second interpolated
output data 71b calculated in the interpolated output data
calculation section 71 by the output correction factor F calculated
in the correction factor calculation section 73 (SP6, SP7).
In the control variable calculation section 75, using the turbine
output (generator output) 61a in the predetermined operation
(actual operation) mode, the turbine inlet temperature-equivalent
control variable (CLCSO) in the predetermined operation mode is
determined on the basis of the first modified interpolated output
data 74a and the second modified interpolated output data 74b
output from the interpolated output data modification section 74
(SP8).
Next, in the fuel distribution calculation section 76, the fuel
distribution ratios FDRs related to the first fuel circuit 18 and
the second fuel circuit 19 in the predetermined operation (actual
operation) mode are calculated using the relation between the pilot
ratio PR and the turbine inlet temperature-equivalent control
variable (CLCSO) shown in FIG. 5. Specifically, the pilot ratio PR,
i.e., the fuel distribution ratio FDR for the first fuel circuit
18, is calculated from the relation shown in FIG. 5 using the
turbine inlet temperature-equivalent control variable (CLCSO)
calculated on the basis of the modified interpolated output data
(first modified interpolated output data 74a and second modified
interpolated output data 74b) obtained by correcting the
interpolated output data on normal operation (first interpolated
output data 71a and second interpolated output data 71b) (SP9). The
fuel distribution ratio FDR for the second fuel circuit 19 can be
calculated by subtracting the fuel distribution ratio FDR for the
first fuel circuit 18 from the total fuel flow rate being 1 (100%)
(SP10).
Next, in the fuel valve opening setting section 81 of the valve
opening setting unit 80, the valve openings of the pilot fuel
regulating valve 23 and the main fuel regulating valve 24 are set
on the basis of the fuel distribution ratios FDRs for the
respective first fuel circuit 18 and second fuel circuit 19
calculated in the fuel distribution calculation section 76. The
valve opening command values PVS, MVS are output to the pilot fuel
regulating valve 23 and the main fuel regulating valve 24 (SP11,
SP12).
According to Embodiment 1, even when the gas turbine is switched
from normal operation to anti-icing operation, the generator output
is maintained and the turbine inlet temperature-equivalent control
variable (CLCSO) is properly corrected relative to an increase in
amount of bleed air, so that stable combustion control can be
maintained.
Moreover, according to this embodiment, it is possible to realize
stable operation of the gas turbine while meeting emission
regulation values of NO.sub.R, CO, etc. even during turndown
operation.
Embodiment 2
Next, Embodiment 2 will be described with reference to FIG. 10 to
FIG. 12.
This embodiment is different from Embodiment 1 in that a first
database 90a related to the first operation mode and a second
database 90b related to the second operation mode are prepared, and
that a modified turbine inlet temperature-equivalent control
variable (MCLCSO) in the predetermined operation (actual operation)
mode is calculated from these databases.
In other words, the two embodiments are different in that the
database 70a with reference only to the first operation mode is
used in Embodiment 1 while the databases 90a, 90b with reference to
both the first operation mode and the second operation mode are
used in Embodiment 2.
In FIG. 10, as preparation, the first database 90a related to the
first operation mode and the second database 90b related to the
second operation mode are created of the relations between the
control parameters and the turbine output (generator output MW) in
a fuel distribution setting unit 90 on the basis of the input data
61 on the measurement values and the external command values
(output command value (MW) and anti-icing command value (AID))
output from the input unit 60. The configuration of each database
in this embodiment is the same as in Embodiment 1.
Although the combustion control device 50 of this embodiment is
composed of the input unit 60, the fuel distribution setting unit
90, and the valve opening setting unit 80 as in Embodiment 1, the
configuration of the fuel distribution setting unit 90 of
Embodiment 2 is different from that of Embodiment 1. Specifically,
the fuel distribution setting unit 90 includes a turbine inlet
temperature-equivalent control variable setting section 91 and a
fuel distribution correction section 92.
The turbine inlet temperature-equivalent control variable setting
section 91 functions to calculate the turbine inlet
temperature-equivalent control variable (CLCSO) related to the
first operation mode and the second operation mode. That is, the
turbine inlet temperature-equivalent control variable setting
section 91 calculates first interpolated output data 91a on no load
operation and second interpolated output data 91b on rated load
operation from the first database 90a related to the first
operation mode. Similarly, the turbine inlet temperature-equivalent
control variable setting section 91 calculates third interpolated
output data 91c on no load operation and fourth interpolated output
data 91d on rated load operation from the second database 90b
related to the second operation mode.
Next, first interpolated data 91e equivalent to a turbine inlet
temperature-equivalent control variable (CLCSO1) in the first
operation mode is calculated from the first interpolated output
data 91a and the second interpolated output data 91b related to the
first operation mode. Second interpolated data 91f equivalent to a
turbine inlet temperature-equivalent control variable (CLCSO2) in
the second operation mode is calculated from the third interpolated
output data 91c and the fourth interpolated output data 91d related
to the second operation mode. The procedure of calculating the
first interpolated data 91e and the second interpolated data 91f
from the databases 90a, 90b on the respective first operation mode
and second operation mode is the same as the procedure described in
Embodiment 1. The calculated first interpolated data 91e and second
interpolated data 91f are output to a control variable
interpolation section 93 of the fuel distribution correction
section 92.
The fuel distribution correction section 92 includes the control
variable correction section 93 that calculates the modified turbine
inlet temperature-equivalent control variable (MCLCSO) by
correcting the turbine inlet temperature-equivalent control
variables (CLCSO1, CLCSO2) calculated in the turbine inlet
temperature-equivalent control variable setting section 91, and a
fuel distribution calculation section 94 that sets the fuel
distribution ratios FDRs for the fuel circuits 18, 19 from the
modified turbine inlet temperature-equivalent control variable
(MCLCSO).
Specifically, the control variable interpolation section 93
functions to calculate the modified turbine inlet
temperature-equivalent control variable (MCLCSO) in the
predetermined operation (actual operation) mode on the basis of the
first interpolated data 91e equivalent to the turbine inlet
temperature-equivalent control variable (CLCSO1) related to the
first operation mode and the second interpolated data 91f
equivalent to the turbine inlet temperature-equivalent control
variable (CLCSO2) related to the second operation mode, both
transmitted from the turbine inlet temperature-equivalent control
variable setting section 91.
The concept of calculating the modified turbine inlet
temperature-equivalent control variable (MCLCSO) will be
specifically described with reference to FIG. 11. FIG. 11 shows a
relation between the turbine inlet temperature-equivalent control
variable (CLCSO) and the casing pressure ratio (CPR) in the
operation modes in the case where the casing pressure ratio is
selected as the specific parameter. The turbine inlet
temperature-equivalent control variable (CLCSO) is represented on
the vertical axis, and the casing pressure ratio (CPR) is
represented on the horizontal axis. While the casing pressure ratio
(CPR) is described here as an example of the specific parameter,
the same concept is applicable to other specific parameters as
well.
The turbine inlet temperature (TIT) is proportional to the turbine
output (generator output MW). If the IGV opening is constant, the
turbine inlet temperature (TIT) is also proportional to the casing
pressure ratio (CPR). The turbine inlet temperature-equivalent
control variable (CLCSO) is a dimensionless value of the turbine
inlet temperature (TIT) as described above. Accordingly, if the IGV
opening is constant, the turbine inlet temperature-equivalent
control variable (CLCSO) is proportional to the casing pressure
ratio (CPR) and the turbine output (generator output MW). Thus, as
shown in FIG. 11, if the IGV opening is constant, the relation
between the turbine inlet temperature-equivalent control variable
(CLCSO) and the casing pressure ratio (CPR) is represented by a
linear relation.
In FIG. 11, the first operation mode is indicated by the dashed
line as the line L1, while the second operation mode is indicated
by the solid line as the line L2. In anti-icing operation, part of
the casing air is extracted and circulated to the air intake
facility 7, so that the casing pressure decreases and the fuel-air
ratio inside the combustors increases. Therefore, when anti-icing
operation is started, the turbine inlet temperature-equivalent
control variable (CLCSO) becomes higher than that in normal
operation (first operation mode) in which anti-icing operation is
not performed. That is, if the casing pressure ratio is the same,
the turbine inlet temperature-equivalent control variable (CLCSO)
is higher in the second operation mode than in the first operation
mode.
In FIG. 11, the casing pressure ratio in the first operation mode
and the casing pressure ratio in the second operation mode are
denoted by CP1, CP2, respectively, and the turbine inlet
temperature-equivalent control variables (CLCSOs) in the first and
second operation modes are denoted by CLCSO1, CLCSO2, respectively.
When the point on the line L1 corresponding to the casing pressure
ratio in the first operation mode (CP1) is referred to as a point P
and the point on the line L2 corresponding to the casing pressure
ratio in the second operation mode (CP2) is referred to as a point
Q, the turbine inlet temperature-equivalent control variables
corresponding to the points P, Q are equivalent to CLCSO1,
CLCSO2.
Next, the casing pressure ratio in the predetermined operation
(actual operation) mode is denoted by CPS, and the point on the
line L3, which connects the points P, Q on the lines L1, L2,
corresponding to the casing pressure ratio CPS is referred to as a
point S. When the turbine inlet temperature-equivalent control
variable corresponding to the point S is denoted by CLCSOS, this
value is equivalent to the modified turbine inlet
temperature-equivalent control variable (MCLCSO) in the
predetermined operation (actual operation) mode. Thus, the relation
among the turbine inlet temperature-equivalent control variables
CLCSO1, CLCSO2, CLCSOS and the casing pressure ratios CP1, CP2, CPS
is expressed by the following formula (2):
CLCSOS=CLCSO1+(CLCSO2-CLCSO1).times.(CPS-CP1)/(CP2-CP1) (2)
Accordingly, it is possible to calculate the turbine inlet
temperature-equivalent control variable (CLCSOS) in the
predetermined operation (actual operation) mode, from the casing
pressure ratio in the first operation mode (CP1), the casing
pressure ratio in the second operation mode (CP2), and the casing
pressure ratio in the predetermined operation (actual operation)
mode (CPS), by linearly interpolating the turbine inlet
temperature-equivalent control variables in the first operation
mode and the second operation mode (CLCSO1, CLCSO2). This turbine
inlet temperature-equivalent control variable (CLCSOS) is
equivalent to the modified turbine inlet temperature-equivalent
control variable (MCLCSO) in the predetermined operation (actual
operation) mode. While the interpolation method has been described
above, the present invention is not limited thereto; for example,
even when the casing pressure ratio (CPS) is smaller than the
casing pressure ratio (CP2), the modified turbine inlet
temperature-equivalent control variable (MCLCSO) in the
predetermined operation mode can be similarly calculated by using a
liner extrapolation method.
Next, in the fuel distribution calculation section 94, the fuel
distribution ratios FDRs related to the first fuel circuit 18 and
the second fuel circuit 19 in the predetermined operation mode are
calculated using the modified turbine inlet temperature-equivalent
control variable (MCLCSO) calculated in the control variable
interpolation section 93. The calculation procedure of the fuel
distribution ratios FDRs is the same as the method of Embodiment 1
described with reference to FIG. 5, and therefore the details
thereof will be omitted. The calculated fuel distribution ratios
FDRs for the first fuel circuit 18 and the second fuel circuit 19
are output to the fuel valve opening setting section 81 of the
valve opening setting unit 80.
In the fuel valve opening setting section 81, the valve openings of
the pilot fuel regulating valve 23 of the first fuel circuit 18 and
the main fuel regulating valve 24 of the second fuel circuit 19 are
set. As the setting procedure of the valve openings of the valves
is the same as in Embodiment 1, the details thereof will be
omitted. The determined valve openings are output to the pilot fuel
regulating valve 23 and the main fuel regulating valve 24. When the
top-hat fuel regulating valve (not shown) is used, the valve
opening can be set by the same procedure as with the pilot fuel
regulating valve.
Next, the process flow of a control method according to Embodiment
2 will be described on the basis of FIG. 12. The process flow that
is different from the method of Embodiment 1 shown in FIG. 9 is
indicated as thick-lined blocks in FIG. 12.
As in Embodiment 1, the measurement values, the various valve
openings, and the external command values are transmitted to the
input unit 60, and output as the input data 61 to the fuel
distribution setting unit 90 (SP1).
Next, as a preparatory processing task, the database 90a and the
database 90b are created of the relations between the control
parameters and the turbine output (generator output MW) in the fuel
distribution setting unit 90 (SP2). The databases 90a, 90b related
to the first operation mode and the second operation mode will be
referred to as the first database 90a and the second database 90b,
respectively. In this embodiment, the casing pressure ratio (CPR)
is shown as a typical example of the specific parameter to be
selected, but other specific parameters can also be used as in
Embodiment 1.
Next, the first interpolated output data 91a on no load operation
and the second interpolated output data 91b on rated load operation
are calculated using the first database 90a on the first operation
mode (SP3). Then, the first interpolated data 91e equivalent to the
turbine inlet temperature-equivalent control variable (CLCSO1) in
the first operation mode is calculated on the basis of the first
interpolated output data 91a and the second interpolated output
data 91b (SP4). The procedure of calculating the turbine inlet
temperature-equivalent control variable (CLCSO) from the database
is the same as the procedure described in Embodiment 1.
Next, the third interpolated output data 91c on no load operation
and the fourth interpolated output data 91d on rated load operation
are calculated using the second database 90b on the second
operation mode (SP5). Then, the second interpolated data 91f
equivalent to the turbine inlet temperature-equivalent control
variable (CLCSO2) in the second operation mode is calculated on the
basis of the third interpolated output data 91c and the fourth
interpolated output data 91d (SP6).
Next, the modified turbine inlet temperature-equivalent control
variable (MCLCSO) in the predetermined operation (actual operation)
mode is calculated on the basis of the first interpolated data 91e
on the first operation mode and the second interpolated data 91f on
the second operation mode (SP7). The procedure of calculating the
modified turbine inlet temperature-equivalent control variable
(MCLCSO) in the predetermined operation (actual operation) mode by
interpolating the turbine inlet temperature-equivalent control
variable (CLCSO1) and the casing pressure ratio (CP1) in the first
operation mode and the turbine inlet temperature-equivalent control
variable (CLCSO2) and the casing pressure ratio (CP2) in the second
operation mode is the same as the procedure described using FIG.
11.
Next, the fuel distribution ratios FDRs for the first fuel circuit
18 and the second fuel circuit 19 are calculated on the basis of
the modified turbine inlet temperature-equivalent control variable
(MCLCSO) in the predetermined operation (actual operation) mode
(SP8, SP9). The valve openings PVS, MVS of the pilot fuel
regulating valve 23 of the first fuel circuit 18 and the main fuel
regulating valve 24 of the second fuel circuit 19 can be selected
on the basis of the calculated fuel distribution ratios FDRs for
the first fuel circuit 18 and the second fuel circuit 19 (SP10,
SP11).
According to the aspect of this embodiment, compared with
Embodiment 1, the turbine inlet temperature-equivalent control
variable (CLCSO) is calculated by interpolating the database on
anti-icing operation and the database on normal operation, so that
the turbine inlet temperature-equivalent control variable (CLCSO)
can be set more accurately than in Embodiment 1. Thus, even when
anti-icing operation is started, more stable combustion control can
be realized.
Moreover, according to this embodiment, as in Embodiment 1, it is
possible to realize stable operation of the gas turbine while
meeting emission regulation values of NO.sub.R, CO, etc. even
during turndown operation.
Embodiment 3
Next, Embodiment 3 will be described with reference to FIG. 13.
In both Embodiment 1 and Embodiment 2, the relations between the
turbine output (generator output MW) or the turbine inlet
temperature and the control parameters are made into a database on
the basis of the input data (input data group) 61 transmitted from
the input unit 60, and the fuel distribution ratios for the fuel
circuits and the valve openings are set on the basis of the
database. Embodiment 3 is different from Embodiment 1 and
Embodiment 2 in that the relations between the turbine inlet
temperature (TIT) and the input data 61 are made into a database
without using any control parameter, and the valve openings of the
valves are set on the basis of the database.
While the configuration of the database in this embodiment is
different from that of the other embodiments, the basic concept of
the modification method, in which a database related to the first
operation mode and a database related to the second operation mode
are prepared and a modified turbine inlet temperature or a modified
turbine inlet temperature-equivalent control variable in the
predetermined operation mode is calculated from the databases, is
the same as that of Embodiment 2. Here, the turbine inlet
temperature (TIT), other than the turbine inlet
temperature-equivalent control variable (CLCSO), is included in the
objects to be calculated from the databases, because the turbine
inlet temperature (TIT) and the turbine inlet
temperature-equivalent control variable (CLCSO) are proportional to
each other as described above, and therefore the turbine inlet
temperature-equivalent control variable (CLCSO) can be substituted
by the turbine inlet temperature (TIT).
In FIG. 13, as preparation, a first general database 100a related
to the first operation mode and a second general database 100b
related to the second operation mode are created of the relations
between the turbine inlet temperature (TIT) and the input data 61
in a fuel distribution setting unit 100 on the basis of the input
data 61 related to the measurement values, the control values, and
the external command values output from the input unit 60.
A turbine inlet temperature-equivalent control variable setting
section 101 functions to set interpolated data 101a, 101b
equivalent to the turbine inlet temperature (TIT) or the turbine
inlet temperature-equivalent control variable (CLCSO) in the first
operation mode and the second operation mode. Specifically, the
turbine inlet temperature-equivalent control variable setting
section 101 calculates the first interpolated data 101a equivalent
to a turbine inlet temperature (TIT1) or the turbine inlet
temperature-equivalent control variable (CLCSO1) in the first
operation mode on the basis of the first general database 100a
related to the first operation mode. Moreover, the turbine inlet
temperature-equivalent control variable setting section 101
calculates the second interpolated data 101b equivalent to a
turbine inlet temperature (TIT2) or the turbine inlet
temperature-equivalent control variable (CLCSO2) in the second
operation mode on the basis of the second general database 100b
related to the second operation mode. Both pieces of data are
output to a control variable interpolation section 103 of a fuel
distribution correction section 102.
The control variable interpolation section 103 functions to set a
modified turbine inlet temperature (MTIT) or the modified turbine
inlet temperature-equivalent control variable (MCLCSO) in the
predetermined operation (actual operation) mode on the basis of the
first interpolated data 101a and the second interpolated data 101b
output from the turbine inlet temperature-equivalent control
variable setting section 101. Specifically, using the specific
parameter, the control variable interpolation section 103
calculates the modified turbine inlet temperature (MTIT) or the
modified turbine inlet temperature-equivalent control variable
(MCLCSO) from the first interpolated data 101a on the first
operation mode and the second interpolated data 101b on the second
operation mode. One example of the specific parameter is the casing
pressure ratio (CPR).
To calculate the modified turbine inlet temperature (MTIT) or the
modified turbine inlet temperature-equivalent control variable
(MCLCSO) in the predetermined operation mode, the linear
interpolation or extrapolation method of Embodiment 2 described
using FIG. 11 can be applied. In the case where FIG. 11 of
Embodiment 2 is applied to this embodiment, the turbine inlet
temperature-equivalent control variable (CLCSO) on the vertical
axis may be substituted by the turbine inlet temperature (TIT).
Instead of the casing pressure ratio (CPR), other specific
parameters may be used as the specific parameter. The calculated
modified turbine inlet temperature (MTIT) or the modified turbine
inlet temperature-equivalent control variable (MCLCSO) is output to
a fuel distribution calculation section 104.
In the fuel distribution calculation section 104, the fuel
distribution ratios FDRs related to the first fuel circuit 18 and
the second fuel circuit 19 in the predetermined operation (actual
operation) mode are calculated using the modified turbine inlet
temperature (MTIT) or the modified turbine inlet
temperature-equivalent control variable (MCLCSO) transmitted from
the control variable interpolation section 103. The procedure of
calculating the fuel distribution ratios FDRs is the same as that
of Embodiment 1, and therefore the details thereof will be omitted.
The calculated fuel distribution ratios FDRs for the first fuel
circuit 18 and the second fuel circuit 19 are output to the fuel
valve opening setting section 81 of the valve opening setting unit
80.
The fuel valve opening setting section 81 sets the valve openings
of the pilot fuel regulating valve 23 of the first fuel circuit 18
and the main fuel regulating valve 24 of the second fuel circuit
19. The procedure of setting the valve opening of each valve is the
same as that of Embodiment 1. The set valve opening command values
PVS, MVS are output to the pilot fuel regulating valve 23 and the
main fuel regulating valve 24.
Next, FIG. 14 shows the process flow of a control method according
to Embodiment 3. The process flow that is different from the
methods of Embodiment 1 and Embodiment 2 is indicated as
thick-lined blocks. As described above, in this embodiment, the
relations between the turbine inlet temperature (TIT) and the input
data group are made into the databases on the first operation mode
and the second operation mode (first general database 100a and
second general database 100b). It is different from Embodiment 2
that the first interpolated data 101a and the second interpolated
data 101b related to the turbine inlet temperature (TIT) or the
turbine inlet temperature-equivalent control variable (CLCSO) are
calculated using these databases, and that the modified turbine
inlet temperature (MTIT) or the modified turbine inlet
temperature-equivalent control variable (MCLCSO) is calculated from
these pieces of data. The process flow is otherwise the same as
that of Embodiment 2.
According to this embodiment, compared with Embodiment 1 and
Embodiment 2, more stable combustion control can be realized. That
is, in this embodiment, a wider range of measurement values,
control values, and external command values than in Embodiment 1
and Embodiment 2 are incorporated and made into the databases. It
is therefore possible to set the turbine inlet temperature (TIT) or
the turbine inlet temperature-equivalent control variable (CLCSO)
and determine the fuel valve openings with higher accuracy, so that
an unstable combustion state is eliminated and the problems of NO
and combustion oscillation are eliminated.
Moreover, according to this embodiment, even when normal operation
is switched to anti-icing operation, stable combustion control of
the combustors is maintained, so that an increase in NO.sub.x etc.
can be avoided and generation of combustion oscillation can be
suppressed. As a result, stable operation of the gas turbine can be
realized.
Furthermore, according to this embodiment, as in Embodiment 1 and
Embodiment 2, it is possible to realize stable operation of the gas
turbine while meeting emission regulation values of NO.sub.x, CO,
etc. even during turndown operation.
INDUSTRIAL APPLICABILITY
According to the gas turbine combustion control device and
combustion control method and the program therefor, even when
normal operation is switched to anti-icing operation, stable
combustion control of the combustors is maintained, so that an
increase in NO etc. can be avoided and generation of combustion
oscillation can be suppressed. As a result, stable operation of the
gas turbine can be realized. Moreover, it is possible to realize
stable operation while meeting emission regulation values even
during turndown operation (partial load operation).
REFERENCE SIGNS LIST
1 Gas turbine 2 Compressor 3 Combustor 4 Turbine 5 Generator 6
Casing 7 Air intake facility 8 Rotating shaft 11 Air intake duct 12
Bleed air pipe 13 Exhaust duct 14 Turbine bypass pipe 15 Pilot
nozzle 16 Main nozzle 17 Fuel main circuit 18 First fuel circuit 19
Second fuel circuit 20 Inlet guide vane (IGV) 21 IGV driving unit
22 Air bleed valve 23 Pilot fuel regulating valve 24 Main fuel
regulating valve 25 Turbine bypass valve 30 Casing temperature
indicator 31 Casing pressure indicator 32 Atmospheric temperature
indicator 33 Atmospheric pressure indicator 34 Intake air
temperature indicator 35 Intake air pressure indicator 36 Bleed air
flowmeter 37 Fuel flowmeter 38 Fuel temperature indicator 39 Waste
gas temperature indicator 40 Generator output detection unit 50
Combustion control device 60 Input unit 61 Input data 61a Generator
output 61b IGV opening 61c Intake air temperature 61d Intake air
flow rate 61e Turbine bypass flow rate 61f, .DELTA.T Intake air
temperature difference 61g Atmospheric temperature 61h, CPR Casing
pressure ratio 61i Amount of bleed air 61j Intake air pressure 61k
Atmospheric pressure 61m Air bleed valve opening 61p Casing
pressure 70, 90, 100 Fuel distribution setting unit 80 Valve
opening setting unit 70a, 90a, 90b, 100a, 100b Database 71
Interpolated output data calculation section 71a, 91a First
interpolated output data 71b, 91b Second interpolated output data
72 Interpolated output data correction section 73 Correction factor
calculation section 74 Interpolated output data modification
section 74a First modified interpolated output data 74b Second
modified interpolated output data 75 Control variable calculation
section 76, 94, 104 Fuel distribution calculation section 81 Fuel
valve opening setting section 91, 101 Turbine inlet
temperature-equivalent control variable setting section 91c Third
interpolated output data 91d Fourth interpolated output data 91e,
101a First interpolated data 91f, 101b Second interpolated data 92,
102 Fuel distribution correction section 93, 103 Control variable
interpolation section AID Anti-icing command value MW Turbine
output command value F Output correction factor FDR Fuel
distribution ratio PR Pilot ratio TIT Turbine inlet temperature
MTIT Modified turbine inlet temperature CLCSO Turbine inlet
temperature-equivalent control variable MCLCSO Modified turbine
inlet temperature-equivalent control variable
* * * * *